Django常用组件之分页器

目录

• 循环插入数据测试
• 实现分页器
  • 视图层使用
  • 模板层使用

循环插入数据测试

# ORM 帮我们提供了循环插入数据更快捷的方法：
book_list = []
for i in range(1000):
    book_list.append(models.Book(title='第%s本书'%i))
    models.Book.objects.bulk_create(book_list)

实现分页器

在app01文件夹中新建utils目录，新建自己实现的分页器方法mypage.py

class Pagination(object):
    def __init__(self,current_page,all_count,per_page_num=2,pager_count=11):
        """
        封装分页相关数据
        :param current_page: 当前页
        :param all_count:    数据库中的数据总条数
        :param per_page_num: 每页显示的数据条数
        :param pager_count:  最多显示的页码个数

        用法:
        queryset = model.objects.all()
        page_obj = Pagination(current_page,all_count)
        page_data = queryset[page_obj.start:page_obj.end]
        获取数据用page_data而不再使用原始的queryset
        获取前端分页样式用page_obj.page_html
        """
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1

        if current_page <1:
            current_page = 1

        self.current_page = current_page

        self.all_count = all_count
        self.per_page_num = per_page_num

        # 总页码
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager

        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)

    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_num

    @property
    def end(self):
        return self.current_page * self.per_page_num

    def page_html(self):
        # 如果总页码 < 11个：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 总页码  > 11
        else:
            # 当前页如果<=页面上最多显示11/2个页码
            if self.current_page <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1

            # 当前页大于5
            else:
                # 页码翻到最后
                if (self.current_page + self.pager_count_half) > self.all_pager:
                    pager_end = self.all_pager + 1
                    pager_start = self.all_pager - self.pager_count + 1
                else:
                    pager_start = self.current_page - self.pager_count_half
                    pager_end = self.current_page + self.pager_count_half + 1

        page_html_list = []
        # 添加前面的nav和ul标签
        page_html_list.append('''
                    <nav aria-label='Page navigation>'
                    <ul class='pagination'>
                ''')
        first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
        page_html_list.append(first_page)

        if self.current_page <= 1:
            prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)

        page_html_list.append(prev_page)

        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
            else:
                temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
            page_html_list.append(temp)

        if self.current_page >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一页</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
        page_html_list.append(next_page)

        last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)
        # 尾部添加标签
        page_html_list.append('''
                                           </nav>
                                           </ul>
                                       ''')
        return ''.join(page_html_list)

视图层使用

from app01.utils.mypage import Pagination
def boot_list(request):
    book_list = models.Book.objects.all()
    # 自定义分页器的使用
    current_page = request.GET.get('page',1)
    all_count = book_list.count()
    page_obj = Pagination(current_page=current_page,
                          all_count=all_count,
                          per_page_num=15,
                          pager_count=11)
    # 参数说明：
    # current_page 当前的页数
    # all_count 所有的页数
    # per_page_num 每页显示多少
    # pager_count 分页器显示的条数
    page_queryset = book_list[page_obj.start:page_obj.end]
    return render(request,'book_list.html',locals())

模板层使用

在对书的列表循环取值的时候，换掉循环的对象：

{% for book_obj in page_queryset %}
 <!--将页面上原本的book_list对象全部换成切片之后的queryset即可-->

然后，在表格标签下面需要加分页功能的地方加上即可。

{{ page_obj.page_html|safe }}